Vibration dumbbell



FIG. 1 is a perspective view of a vibration dumbbell, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines represent a portion of the structure that forms no part of the claim. 

The ornamental design for a vibration dumbbell, as shown and described. 